Childpsy

Goal: Using GPower to compute the sample size needed

1. Download GPower by visiting this web site: http://www.gpower.hhu.de 
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2. Extract the GPower folder
3. Double-click the “GPowerSetup.msi” to install the GPower

• Sample size for two-tailed one-sample t-test

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• Input basic information by pressing the “Determine” button to calculate the effect size

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• Sample size for two-tailed paired-samples t-test

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• Again, you can input basic information by pressing the “Determine” button to calculate the effect size

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• Sample size for two-tailed independent-samples t-test

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• Again, you can input basic information by pressing the “Determine” button to calculate the effect size

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• Sample size for one-way ANOVA with three groups

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• Again, you can input basic information by pressing the “Determine” button to calculate the effect size. You can specify the group means to compute the effect size.

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• Or you can specify the between-group and the within-group variances to calculate the effect size

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• Sample size for the Chi-square test

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• Again, you can input basic information by pressing the “Determine” button to calculate the effect size

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